In the conventional power electronic system, a number of IGBTs, inductors, capacitors, resistors and other components, as the major components of the power part, are installed to the cabinet separately, which means the entire power part is not modularized. Only in few power electronic systems there are a number of IGBTs or inductors, capacitors and resistors integrated into a power electronic device, namely the power part is modularized. Generally, one power electronic system includes a number of power electronic devices.
As shown in FIG. 1, in the conventional power electronic system, each power electronic device comprises a power unit 1, a number of conductive terminals 10 and a number of connection terminals 13. Power lines 14 connected to the power grid are connected to the conductive terminal 10 by screws 20, and the conductive terminals 10 are connected to the power unit 1, as a result, the power line 14 and the power unit 1 are electrically connected. The signal lines 15 are in electrical connection with the power unit 1 via the connection terminals 13. The fixed connection of the power line 14 and the signal line 15 to the power unit 1 limits the moving range of the power unit 1, as a result, there is no free plugging of the power electronic device with respect to the cabinet. If a power electronic device of the power electronic system occurs abnormal, the requirement of shutting down the entire power electronic system for maintenance or replacement would seriously affect the efficiency of the power electronic system.
Therefore, it cannot be achieved that the power electronic device is freely plugged with respect to the cabinet in the conventional power electronic system. Moreover, it cannot be achieved that the failed power electronic device is maintained or replaced in the case that other power electronic devices operate normally. In this case, it is needed to achieve an easy hot plug function.